Electric heating device.



J. A. HEANY.

ELECTRIC HEATING DEVICE.

APPLICATION FILED 001'. 18, 1913.

Patented July 21, 191% Z2 2 I Z duo: "up! UNITED STATES PATENT OFFICE.

ELECTRIC HEATING DEVICE.

Specification ofLetters Patent. Patented July 21, 1E? 14.

Application filed October 18. 1913. Serial no; 795,908.

To all whom it may concern:

Be it known that I, JOHN ALLEN HEANY, a citizen of the United States, and resident of the city of Washington, District of Columbia, have invented certain new and useful Improvements in Electric Heating Devices; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The invention relates to electric heating devices, such as sad irons, cooking devices and the like, designed to employ alternating, pulsating or intermittent currents, which induce eddy currents in the body portion of the heating unit by means of a primary or inducing coil, supplied with current of the character indicated, which coil is located in a groove within the body of the unit. It has been customary heretofore to supply the heat for sad irons, electric stoves and the like, by meansof resistance coils supplied with current, which coils develop in themselves a high degree of heat which is eommunicated by conduction or radiation to the metal of the heating unit proper. Heating devices of this character are generally objectionable for the reason that the heating coils are liable to burn out, to become shortcircuited or otherwise deranged or disabled due to the high heat developed. Ac ording to the present invention, the heat is not -le veloped in the primary coil which receives the current from the line, but, on th contrary, the heat is developed dire tly in the body of metal constituting the heating unit in which the coil is carried, the heat being generated by the effect of secondary or eddy currents which are induced by the alternating or interrupted currents flowing in the primary coil.

In the accompanying drawings, Figure 1 1s 1 a perspective view of a sad iron constructed in accordance with the invention. Fig. 2 is a transverse vertical cross section through the same. Fig. 3 a vertical longitudinal cross section thereof. Fig. 4: is a top 'plan view of the lower section of the iron. Fig. 5 is a bottom plan view of the upper section. Fig. 6 is a plan view of a suitable primary coil adapted for use in the heating unit. Fig.

7 is a vertical section through an electric stove embodying the invention.

Referring to Figs. 1 to 6 of the drawings, 1 indicates the lower section of a heating unit in the form of a sad iron, which section comprises a plate-like body of generally triangular form common to sad irons, provided in its upper surface with a groove or recess 3 which is continuous and is conveniently given the form of an annulus surrounding a central core-like section 5. Superposed upon the lower section 1 is an upper section 2 having the same general configuration as the lower section and serving to cover the lower section and inclose the primary coil which is applied to the lower section. To effect this result, the upper section maybe provided with a smooth plain under surface, but in the preferred form of the invention, the upper section is also provided with a groove 4.- of the same character as the groove 3 in the lower section, so that when the two sections are secured together, the body of the iron formed by the two sections land 2, 5 is provided with an annular groove or chamiber surrounding a central core made up of lthe registering bosses 5 and 6 on the lower i and upper sections respectively. Located within the groove, recess or an- ;uular chamber within the body of the iron is a primary coil 7 consisting of'the requisite number of turns of insulated wire to form a ring-like coil which occupies practically the entire space within the groove or chamber aforesaid. Preferably, the wire constituting the coil 7 is insulated with an asbestos or other fireproof covering and the several conwrappings of fireproof tape or the like so applied as to retain the coil in its normal shape. The ends of the coil 7 are led out of the rear of the iron through an opening formed by registering grooves 8 and 9 in the respective sections 1 and 2, and said coil ends are connected with a conductor cord the source of electric current by any appropriate coupling means. Preferably, the conductor cord is provided at that portion thereof adjacent the iron with a sheathing or wrapping of wire 10 to hold th'e routine tor cord in proper relation and'prerent the same being damaged. A metal cover plate 16 secured to the rear face of the iron is provided as a further guard or protecting means for the conductor cord where the latter enters the iron.

The two sections 1 and 2 aresecured together preferably by screws 13 which pass through holes 11 in the upper section and volutions of the coil are bound together by i which is adapted to afford connection with (all engage screw-threaded sockets 12 in the lower section :1, as indicated in Figs. 3, 4 and 5. Said screws 13 also serve to secure the handle 14 to the iron, as clearly shown in Figs. 1 and 2. To one side of the handle is secured a clip 15 which embraces the conductor cord and holds the same in upright position, as shown in Fig. 1.

The two sections 1 and 2 of the iron are preferably made of soft steel and are worked to appropriate form in any suitable manner. In assemblingthe parts, the primary coil 7 is inserted in the groove 8 of the lower member 1, after which the upper member is superposed on the lower member so that the projecting portion of the coil 7 enters the groove 4 in the upper member and the terminals of the coil pass out of the rear of the iron through the opening formed by the registering slots 8 and 9. The two sections are then secured together and the handle fastened to the upper section by means of the screws 13. The cover plate 16 is screwed in position and the slip 15 applied to the cord conductor and the apparatus is ready for use.

Upon supplying the coil 7 with alternating, pulsating or intermittent current, the said coil acts as the primary of a transformer, the secondary of which is formed by the metal constituting the body of the iron so that the alternating or pulsating current flowing in coil 7 generates in the metal of the iron surroundingand inclosing the coil, eddy currents which generate heat, due to the hysteresis effect, and the generated heat is conducted'to all parts of the body ofthe iron so that in a very short time the entire mass constituting the body of the iron is at a substantially uniform temperature. In actual practice, it is found that a current which will not materially raise the temperature of coil 7 when the latter is removed from the iron will nevertheless when applied to the heating unit generate secondary or eddy currents, by induction, in the body of the heating unit sufficient to raise the temperature of the iron to the necessary degree for laundry or even cooking purposes. It will also be noted that the coil 7 does not attain a higher heat than the body portion of the iron or heating unit, and this heat is not due to the resistance of the coil .at all, but to the heat conducted from the body of the heating'unit to the coil. By properly insulating the wire forming the coil, this indirect heating of the coil will have no injurious effect on the latter.

As indicated, the invention is also applicable to heating units for culinary and similar purposes, and when-so applied, it may conveniently take the form of an electric stove or heater of the type indicated in ,Fig. 7, in which 1 indicates the main section or body portion of the heating unit provided with an annular groove 3 surrounding a' central coref5 and containing a heating coil 7 of the same general character as the coil 7 employed in connection with the sad iron hereinbefore described. The main body portion 1 is provided with a plate 2 secured to the under surface thereof by means of screws 15 and the device may be conveniently supported on legs 1". When applied with heating current, the primary coil 7 induces in the magnetic metal of the body portion strong eddy currents which are manifested in the form of heat, which is substantially uniformly distributed throughout the body of the unit,and may be utilized for cooking or any other operations where heat-' ing isrequired. Obviously, the heating unit involving the principles of construction and operation hereinbefore described, may be applied to various other purposes, without departing from the invention.

What I claim is 1. An electric heating unit employing alternating or pulsating currents comprising two solid plate-like sections of metal having high hysteretic properties, one of said plates being provided on its inner face with an annular recess, and an electric ring-like coil positioned in said recess composed of a plurality of superposed helical turns, said sections being united to completely embed and inclose the coil in the metal thereof, a portion of which forms asolid core for the coil.

2. :An electric heating unit employing alternating or pulsating currents comprising two solid plate-like sections of metal having high hysteretic properties, said sections being provided on their meeting faces with registering annular grooves, afid an electric ring-like coil positioned in the opening formed by said grooves, said coil comprising a plurality of superposed helical turns and said section being unitedto completely embed and in'close the coil in the metal thereof, a portion of which forms a solid core for said coil.

In testimony whereof'I aifix my signature, in presence of two witnesses.

JOHN ALLEN HEANY.

. Witnesses:

FREnaB. MAoLAnaN, ARTHUR BRYANT. 

